SF3B1 and myelodysplastic syndrome: According to genetic abnormalities, MDS are subtyped into: (A) MDS with low blasts and isolated del(5q)—5q deletion, bone marrow blasts (BMB) < 5% in bone marrow and peripheral blasts (PB) < 2%; and SF3B1 or TP53 mutation; (B) MDS with low blasts and SF3B1 mutation—absence of 5q deletion, BMB < 5% and PB < 2%, SF3B1 mutation, and ≥15% ring sideroblasts; and (C) MDS with biallelic TP53 inactivation—equal to or more than two TP53 mutations or one mutation with TP53 copy number loss or copy neutrality, resulting in loss of heterozygosity, complex cytogenetics, BMB, and PB < 20%.